Handler was born in San Francisco, California. He attended Commodore Sloat Elementary, Herbert Hoover Middle School and Lowell High School. Handler graduated from Wesleyan University in 1992. He is an alumnus of the San Francisco Boys Chorus.
Handler is married to Lisa Brown, a graphic artist whom he met in college.They have a son, Otto, born in 2003. They live in an old Victorian house in San Francisco. Handler's mother is retired City College of San Francisco Dean, Sandra Handler, and his father, Louis Handler, is an accountant. He also has a younger sister, Rebecca Handler.
Handler is politically active and helped form LitPAC. In the June 10, 2007 edition of The New York Times Magazine, Handler reveals ambivalence toward his wealth, and the expectations it creates. He states he is often asked for money for charitable causes and often gives. In an interview conducted by the 667 Dark Avenue fan site, Daniel Handler gave his personal philosophy as "Never refuse a breath mint".
Although Handler has a Jewish background and considers C. S. Lewis to be an influence (Hilliard 2005), he describes himself as a secular humanist. In addition, he says "I'm not a believer in predetermined fates, being rewarded for one's efforts. I'm not a believer in karma. The reason why I try to be a good person is because I think it's the right thing to do. If I commit fewer bad acts there will be fewer bad acts, maybe other people will join in committing fewer bad acts, and in time there will be fewer and fewer of them"
Daniel Handler is the author of the bestselling A Series of Unfortunate Events (under the pen name of Lemony Snicket), a collection of books for children, and three books for adults: Basic Eight (based on a true story of a teenaged girl who commits murder), Watch Your Mouth (a melodramatic satire of family life), and Adverbs, due out this year.
He also wrote the screenplay for the films A Series of Unfortunate Events, Kill the Poor, and Rick.